[DISCUSSION] Windows 11 Build 26x00 (PC) [24/25H2 Retail- GE-release]

Code:

@echo off
setlocal enabledelayedexpansion
chcp 65001 >nul

set "input=%*"

if "%input%"=="" (
    echo Usage: SetDefaultUserFolder.cmd ^<value^>
    echo Example: SetDefaultUserFolder.cmd MyFolderName
    exit /b 1
)

:: Now call PowerShell for detailed Unicode and reserved name validation
powershell -NoProfile -Command ^
    "$name = '%input%'.Trim();" ^
    "$invalid = [System.IO.Path]::GetInvalidFileNameChars() + @('@', '.', ';', '=', ',', '+');" ^
    "if ([string]::IsNullOrWhiteSpace($name)) { Write-Host '[ERROR] Name is empty or whitespace.'; exit 1 }" ^
    "elseif ($name.Length -gt 16) { Write-Host '[ERROR] Name exceeds 16 character limit.'; exit 2 }" ^
    "elseif ($name.EndsWith(' ') -or $name.EndsWith('.')) { Write-Host '[ERROR] Name cannot end with space or dot.'; exit 1 }" ^
    "elseif ('CON','PRN','AUX','NUL','COM1','COM2','COM3','COM4','COM5','COM6','COM7','COM8','COM9','LPT1','LPT2','LPT3','LPT4','LPT5','LPT6','LPT7','LPT8','LPT9' -contains $name.ToUpper()) { Write-Host \"[ERROR] '$name' is a reserved name.\"; exit 1 }" ^
    "elseif ($invalidChar = $name.ToCharArray() | Where-Object { $invalid -contains $_ } | Select-Object -First 1) { Write-Host \"[ERROR] Invalid character found in name: '$invalidChar'\"; exit 1 }" ^
    "else { Write-Host \"[OK] '$name' is a valid folder name.\" }"

if errorlevel 1 (
    echo [ERROR] Folder name validation failed in PowerShell.
    exit /b 4
)

:: Write to registry
reg add HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\UserOOBE /v SetSAMFolderName /t REG_SZ /d "%input%" /f >nul
if %errorlevel% EQU 0 (
    echo [SUCCESS] Default user folder set to: %input%
) else (
    echo [ERROR] Failed to set registry value. %errorlevel%
    exit /b 5
)

exit /b 0